Number of Cu atom(s) in the 1.014 eV photoluminescence copper center and the center’s model in silicon crystal

Number of Cu atom(s) in the 1.014 eV copper center in silicon crystal was determined from an accurately measured relationship between the photoluminescence (PL) intensity of the center and Cu concentration in the crystal. For Cu concentrations lower than about 1×1014 atom/cm3, the PL intensity increased linearly with increasing Cu concentration. From this result and the law of mass action, it was concluded that the Cu center had only one Cu atom in it, contradicting the long-believed pair Cu model. Based on already published data and the present result, a structural model in which the Cu atom was bonded at the center of the Si–Si bond was presented for the Cu center.